In 1995, the United States Federal Aviation Administration (FAA) made a wealth of minute-by-minute radar-based flight tracking data available for distribution to the public with the creation of the Aircraft Situation Display to Industry (ASDI) service. Through this service, flight tracking data is made available to several vendors from a single source. The ASDI information includes the location, altitude, airspeed, origin, destination, estimated time of arrival, tail number, and other data. As a result of the availability of ASDI data, several publically available flight tracking services developed, including several located on the Internet, such as FlightAware.com.
In addition, other sources of flight tracking data are available which may be utilized independently or in combination with the ASDI data to provide flight tracking data to the public. For example, automatic dependent surveillance broadcast (ADS-B) information provides real-time position information that is, in many cases, more accurate than the information available with traditional radar-based systems or from the ASDI service. ADS-B uses GPS signals along with aircraft avionics to transmit an aircraft's location from an on-board transceiver directly to other aircraft as well as to permanent receivers located on the ground. The ground receivers then transmit that information to air traffic controllers, or back to cockpit displays of aircraft equipped with ADS-B avionics, and the like. An aircraft equipped with ADS-B also periodically broadcasts other relevant information such as the aircraft's identification, altitude, and velocity. Currently, this information is broadcast approximately every second.
Additional sources of flight tracking data exist, including EUROCONTROL, the European Organisation for the Safety of Air Navigation, based in Brussels, Belgium, ARINC Incorporated, based in Annapolis, Md., and Airservices Australia, based in Canberra, Australia. Other sources may include government sources, air navigation service providers, airlines, airports, satellite or radio-based tracking operators, and other private entities. However, many of these sources are only willing to provide their data to flight tracking services under agreements requiring that it be shared only with authorized users. Additionally, in the case of certain foreign governments, flight tracking data is provided only for use for specific purposes, such as in conjunction with end users, and thus may not be shared with resellers.
Each potential source of flight tracking data is susceptible of error, inaccuracy and imprecision as to time as well as to aircraft location, heading, altitude, speed, identification, and associated flight plan. Certain data sources are additionally constrained in their geographic coverage, such as by technical limitations or by law. The ability to receive data from many different sources is advantageous. However, when one or more of those sources provides its flight tracking data with a defined access restriction, providing flight tracking data to users becomes a difficult task, as one user may be entitled to view data that is developed using restricted information while another may not.